[PATCH v9 07/13] media: cadence: csi2rx: Soft reset the streams before starting capture

[Jai Luthra]

From: Pratyush Yadav <p.yadav at ti.com>

This resets the stream state machines and FIFOs, giving them a clean
slate. On J721E if the streams are not reset before starting the
capture, the captured frame gets wrapped around vertically on every run
after the first.

Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
Reviewed-by: Maxime Ripard <mripard at kernel.org>
Signed-off-by: Jai Luthra <j-luthra at ti.com>
---
Changes from v8:
    - Simplify reset sequence, minimizing delays

 drivers/media/platform/cadence/cdns-csi2rx.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index 933edec89520..b57e0c3b1944 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -40,6 +40,7 @@
 #define CSI2RX_STREAM_BASE(n)		(((n) + 1) * 0x100)
 
 #define CSI2RX_STREAM_CTRL_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x000)
+#define CSI2RX_STREAM_CTRL_SOFT_RST			BIT(4)
 #define CSI2RX_STREAM_CTRL_START			BIT(0)
 
 #define CSI2RX_STREAM_DATA_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x008)
@@ -134,12 +135,23 @@ struct csi2rx_priv *v4l2_subdev_to_csi2rx(struct v4l2_subdev *subdev)
 
 static void csi2rx_reset(struct csi2rx_priv *csi2rx)
 {
+	unsigned int i;
+
+	/* Reset module */
 	writel(CSI2RX_SOFT_RESET_PROTOCOL | CSI2RX_SOFT_RESET_FRONT,
 	       csi2rx->base + CSI2RX_SOFT_RESET_REG);
+	/* Reset individual streams. */
+	for (i = 0; i < csi2rx->max_streams; i++) {
+		writel(CSI2RX_STREAM_CTRL_SOFT_RST,
+		       csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
+	}
 
-	udelay(10);
+	usleep_range(10, 20);
 
+	/* Clear resets */
 	writel(0, csi2rx->base + CSI2RX_SOFT_RESET_REG);
+	for (i = 0; i < csi2rx->max_streams; i++)
+		writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
 }
 
 static int csi2rx_configure_ext_dphy(struct csi2rx_priv *csi2rx)

-- 
2.41.0